Fluid-pressure motor.



E. W. MEREDITH.

FLUID PRESSURE MOTOR. PPLICATION FILED DEG-23, I915- 1,211,209 Patnted Jan. 2,1917.

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- r E. W. MEREDITH,-

FLUID PRESSURE MOTOR. v APPLICATION FILED DEC-23. 1915.

1,211,209. Patented Jan. 2,1917.

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EDWARD W. MEREDITH, OF BLOOMSBURG, PENNSYLVANIA.

FLUID-PRESSURE MOTOR.

To all whom it may concern."

Be it known that I, EDWARD W. MERE- DITH, a citizen of the United States of America, residing at Bloomsburg, in the county of Columbia and State of Pennsylvania, have invented certain new and useful Improvements in Fluid-Pressure Motors, of the following is a specification.

My present invention relates to improvements in fluid pressure motors and applies directly to the construction of the motor described and claimed in my patent dated November 2, 1915, No. 1158525. In using the structure which forms the subject matter of said patent I find that its operation and efliciency are enhanced by the use of means providing communication at all times, and especially when the parts of the machine are in position so that the fluid pressure is equalized, to maintain an even pressure of the steam even' when the cubical contents of the stem side of the piston is decreasing, as will be hereinafter morefullypointed out.

be stated that the piston In the drawings Figure 1 is a horizontal sectional view of the motor and its connections. Fig. 2 is a plan view, enlarged of the controlling valve. Fig. 3 is a sectional view of the controlling valve and its casing. Fig. 4: is a side elevation of the motor adapted for use as a hydraulic motor with an air chamber forming part of the motor.

I have illustrated the device as either a steam or compressed air motor and also as a hydraulic motor, and while I shall hereinafter refer to these two modifications as steam and hydraulic motors, it will be understood that the invention is capable of use as a single acting engine in many other forms not herein referred to.

For convenience of illustration it may stem 1 and its piston 2 are in direct connection with the table of a brick machine, at the threaded end 3 of the stem, and it will of course be recognized that the table is a reciprocable one and is to be drawn to the right on the working stroke of the piston in its cylinder 4. The table is moved to the left to return the piston, by other power mechanism forming part of the brick machine.

The cylinder is provided with the usual. heads 5 and 6 and has a relief cock 7 opening therein to regulate a cushion of compressed fluid, in the nature of a dash pot in which is the inlet pipe left end of the casing 12, passes around This pipe has cylinder and casing to The valve is also Patented Jan. 2, 1917.

Application filed December 23, 1915. Serial No. 68,381.

the end of the cylinder, at the right, while the head '5 is provided with a usual stufling' box as 8. At 9 and 10 the usual end ports of the cylinder are indicated, the former for admission of fluid and the latter for the exit of fluid or steam.

The motive fluid, or steam for actuating the piston is controlled by the piston valve 11 which is reciprocable in its casing 12 by power such as a cam or crank not shown applied at the end of the stem 13. The casing at one end is in communication with the cylinder 4 through port 9 by the pipe 14 for live steam .to the cylinder for operating the piston. A small branch pipe 14 having a check valve 14 projects from the pipe 14 and communicates with the interior of the cylinder 4 at the left end. The check valve opens toward the cylinder and aids in regulating the pressure therein and this connection by admitting fluid pressure to the cylinder at the left of the piston forms a das of the cylinder, to cushion the piston at the enllx of its stroke to the left.

to the right end of the cylinder and communicates with its interior through the head 6. a check valve 16 therein and the communication is provided between the prevent the formapot at the left end pipe 15 which also extends from the tion of a vacuum at the right end of the cylinder when the piston. moves to the left.

The valve casing is provided with annular recesses or ports 17 and 18, the former for the inlet to the cylinder for the exhaust from the casing, and this port 18 permits passage of exhaust steam to the exhaust pipe 19 of the casing. third port is shown in the valve casing, indicated at 20 and this port is in commumcae, tion with the interior of the cylinder through the cylinder port 10.

Thev valve 11 has a passage 21 therethrough, open at the left end and closed at the right end by the threaded end of the valve stem 13, but at the right end of the piston valve its central bore is provided with four radial ports as 22 which establish communication between the interior of the valve casing and the interior of the valve itself. cut away and its exterior diameter reduced to form an annular space 23 within the casing by meansof which comand the latter .1 in order free flow the "friction munication between the inlet pipe 24 to the casing and inlet ipe 14- of the cylinder through the port I? in the casing. The bore of the casing is grooved M23. and this groove Opens into the port 17 (Figs. 1 and The purpose of this groove is to permit. passage of steam or other motive fluid atall' times, and especially when the valve '11 is in equalizing position (Fig. 1) to maintainan even pressure. This of steam ofisets the fall in pressfire at the stem sideof the piston due to t e decreased cubical volume of the cylin- I have found in. actual use that the iston causes a fall in at'the stem side of the piston when the pressure at that side o the piston istraveling to ing the engine on this stroke.

To understand theutility of maintaining an even pressure on both sides of the piston on the equalization stroke, it will be no- *t1cedthat the piston rod 1 which extends a distance outside the cylinder, makes the 25 piston a differential one, that is'the piston 2'has a greater superficial area in the cylinder on its headside than it has on its rod side, the difference in area being determined by the cross sectional area 0 the piston o'rod. Now suppose thatthe cross section area of the rod is 2 square'in'ches, and we I equalize the pressure in the cylinder say 'at 100 lbs. the greater pressure at the right side of the piston will move itto the left,

5 therefore the piston hasa pressure of 200 i lbs-more on the'h'ead side than on, the rod side. This power is used in overcoming cutting table, but it will be noticed that the 4g fsupplyof live steam is cut off from the cylinder 4 by the valve 11, when the piston 2 is making this stroke and the steam I in the rod end of cylinder 4 is flowing to the. other end of cylinder 4. and around the.

.45 piston 2, and the piston: rod-1 is moving out of cylinder 4 to the atmosphere-thereby increasing the cubical contents of the cylinder 4 inexact pFoportion -to the amount of cubic inches contained in the piston rod 1 that is removed from the .cylinder4 to, the atmosphere through the cylinder head 5 and shifting box 8. As before stated, the live steam is shut off fromthe cylinder and the steam within the cylinder must be reduced in pressure while the piston is making its stroke to the left so that the farther the piston moves to therod end of the cylinder 4 the lower the pressure of equalized steam must be, thereby weakening the en- 0 gine on the latter part of this stroke. This reduction of pressure is caused by the increase of the cubical contents of the cylinder as the the left. Now-to overcome this condition 5 I utilize the groove 23 in the valve casing the left, thus weaken-.

1n the carriage of the brick piston 2 and its rod travel to.

'ieiieoe 12 ,so that when the valve 11 is moved to the equalizing position the cylinder 4- will be in communication with chamber 23 which contains live steam at all times. As the piston 2 moves to the left the steam will flow around'the end of the valve 11, thereby maintaining a constant pressure in the cylinder on the outward stroke of the piston. In'Fig. 4 the motor is illustrated as a hydraulic motor, and I employ a pipe 14 and equip it with a regulating valve 15 and an air chamber- 16' between the controlling valve and the stem side of the piston. This air chamber forms an effectual means for performing the functions of the groove above referred to, and equalizes the pressure of waterthroughout the device.

In Fig. 1 the piston has finished its working stroke and has pulled the table to the right. Admission of live steam to "the casing is cut ofi except to the space 23 but from here the live steam may pass by way of the small groove '23 to port 17 thence through pipe 14 to the left side of the piston and through the centrally bored valve 11' and its ports 22 and ports 20 and 10 to the cylinder at the right side of the piston. By this arrangement of parts the pressure throughout the whole device is equalized, so that the return reciprocation of the power driven table (not shown) will move the piston to the left in Fig. 1. After the piston has been moved to the left, the controlling valve is actuated and moved to the left also and live steam is admitted in large quantities through space. 23, port 17 and pipe 14 to the cylinder at the left of thepiston head, but passage of steam to the right in the casing or through the valve bore is prevented. However, steam is exhausted from the right side of the cylinder through ports 10, 20, 18 22 and pipe 19, a vacuum being prevented by the presence of the check valve 16 as before stated. The

the piston of course moves it to the right and thus the working stroke of the motor is accomplished.

at I claim is 1. In a single acting motor, the combi" nation with its cylinder and its piston, of

'a casing having a valve therein and a motive fluid inlet, ports at the ends of the cylinder in the casing, said valve. having means for equalizing the pressure inthe cylinder upon the returnstroke ofgthe piston and also adapted to admit motive fluid to the cylinder at oneend and exhaust the same from the cylinder at the other end, and means for permitting free flow .of motive fluid throughout the motor when the parts are in position under equalized pressure.

2. In a single acting motor, the combi nation with its communication with ports in a cylinder and its piston, of 13@ a casing having a groove and also a valve ized pressure, said valve having means for therein and a motive fluid inlet, ports at equalizing pressure in the cylinder, and 10 the ends of the cylinder in communication adapted to admit pressure to the cylinder with ports in the casing and one of said at one end and exhaust it from the other casing ports being the terminus of the end of the cylinder.

groove in the casing for permitting free In testimony Whereof I aflix my signafloW of motive fluid throughout the motor ture. when the parts are in position under equal- EDWARD W. MEREDITH. 

